It's usually only the most dog-in-a-handbag of divas who try to police their interviews, so I’m slightly surprised when a request comes in from Gary Clark Jr’s people on the afternoon before I’m due to meet the American blues musician. Could I please steer away from any mentions of Jimi Hendrix, as he comes up a lot and the 29-year-old has become sensitive to the comparison?

Now I am all kinds of lazy but I like to think that I’m capable of looking at a black man with a guitar without instantly declaring that he’s the new Hendrix. Nevertheless, Clark does rather invite the comparison himself by spending almost 10 minutes of this week’s major label debut covering Third Stone From the Sun, the spacey, heavy jam from Are You Experienced.

He does do something different with it, blending it into Little Johnny Taylor’s funky If You Love Me Like You Say and coming up with a guitar effect that mimicks a record turntable scratching. And when I meet him, Shard-tall and thin as a coffee stirrer, he seems so laid- back that if I didn’t know better I’d think he’d only set fire to his guitar if he thought he could smoke it.

Even so, we will avoid incurring the wrath of this smiling, quietly spoken Texan and focus instead on all the living musicians who think he’s the bee’s knees. Following this week’s headlining slot at Highbury Corner’s Garage club — “This is where I want to be, man, up close and sweaty, looking right in people’s faces” — he’ll perform in the rather more polite surroundings of the Albert Hall, supporting Eric Clapton, later in the year.

In 2010 Clark appeared as one of the few youngsters at Clapton’s Crossroads Guitar Festival in Chicago, alongside Jeff Beck, Buddy Guy and BB King. “That gig was pretty major, it definitely flipped a few things. The audience was like, ‘Who’s this new guy?’ That was my big introduction to the world.”

An early thumbs-up from Slowhand is a definite bonus in a field of music where being 90 is a positive boon. Clark, who has played the blues since he got his first guitar at 12, has found a niche where he can be endorsed by the legends while playing in a raw, savage style more reminiscent of cooler upstarts such as The Black Keys.

But he’s also got soul, allowing beats, horns and a smooth voice to take precedence on the title track of his new album, Blak and Blu. On Please Come Home, where he shows off a distinctly un-bluesy falsetto, he sounds like a doo-wop heartbreaker. As his introduction to the mainstream pop world, he recently played on the latest Alicia Keys album.

“I love her stuff, she’s such a soulful singer and player. We come from different genres, I guess you could say, but it’s all good music.”

He says his varied tastes come from growing up in Austin, Texas — home of the SXSW festival and streets with more gig venues than we have Starbucks. “There’s so much music in Austin, and it’s all so different,” he says. “It just seemed natural to soak it all up. I took bits and pieces of all of it.” That’s why his album can include both The Life, a bouncy keyboard number that’s pure pop, and the eight-minute When My Train Pulls In, as bluesy and dirty as a thwack around the head with an Epiphone Casino.

As a headline act, he may still be barely known in this country (the sign on his dressing room door at the Garage spells his surname with an “e”) but he blazes away at his instrument in extraordinary fashion, sending songs spiralling off on volcanic tangents.

In his homeland, this talent has not gone unnoticed. When he was just 17, Austin declared “Gary Clark Jr Day”. I’m disappointed to hear that this did not involve a long parade led by Gary in crown and sceptre, but he still seems chuffed a decade later.

“It was cool. I went to this city council meeting, there was a ceremony, I played a song and they gave me a certificate,” he says. “I’d been playing around town for a few years and I didn’t realise but I was catching a little bit of a buzz. You don’t really see teenagers singing Albert Collins: ‘If trouble was money, I swear I’d be a millonaire’.”

That buzz grew until last year, when he was part of a stellar band including Mick Jagger, BB King and Buddy Guy that performed at a celebration of the blues at the White House. He played in the band that accompanied President Barack Obama singing Sweet Home, Chicago.

“He was pretty good. He’s definitely got swagger,” Clark tells me. Was such an occasion not the tiniest bit intimidating for him? “I try to take it all in my stride. I might have some interesting thoughts in my head but I try not to freak out on a major level. I don’t want to overshadow these really special moments by getting all nervous.”

It’s hard to imagine this cool cat getting nervous about anything as he looks down at his guitar, head nodding, setting it alight with his fingers yet again. He’s made a seamless transition from producing four home-made albums to making one that hit the US top 10 when it came out a few months before we got to hear it. “I’d just count out my gig money, go into a studio for a couple of days and try and knock out as many songs as I could. Then I’d sell them out of my bag.”

Years of being the toast of Austin and a nobody everywhere else have given him the space to become a truly great guitarist. He knows his heritage, having made the trip to Clarksdale, Mississippi where Robert Johnson sold his soul to the devil at the crossroads. “I was driving, I didn’t know where I was, but this feeling came over me. I was like, ‘Woah,’ and 10 seconds later we drove by the crossroads.”

But he’s not too respectful of the traditions either. “There’s definitely a blues police who will come and write you up for not staying in the structure. It just seems like a natural thing to branch out and find your own place, knowing at the same time that what you do is held down by those blues roots.”

A hip, good-looking young dude taking trad guitar music to new places. Jools Holland must be lying awake at night thinking about him. “I got started in that blues world and it changed my life, but I don’t want to recreate the things that my heroes did,” Clark says. “I love music. That’s it.”

Blak and Blu is released this week on Warner Bros. Gary Clark Jr supports Eric Clapton from May 17-26 at the Royal Albert Hall, SW7 (020 7589 8212, royalalberthall.com).